1. Field of the Invention
The present invention relates to a laser processing apparatus and solid laser resonator for processing, for example, printing, through irradiation of an object to be processed with a laser beam, including a laser marking apparatus.
2. Description of the Related Art
Using a laser processing apparatus, a predetermined region is scanned with a laser beam, and the surface of the object to be processed (workpiece), for example parts or products, is irradiated with a laser beam so as to be processed, for example through printing or marking. FIG. 33 shows an example of the configuration of a laser processing apparatus. The laser processing apparatus shown in this figure includes a laser control portion 901, a laser output portion 902 and an input portion 904. Pumping light generated by a laser pumping portion 910 of the laser control portion 901 is transferred to the laser output portion 902 so that a solid laser medium 921 which forms a resonator in a laser resonant portion 920 can be irradiated, and thus, laser oscillation is generated. Laser oscillation light is emitted through an end surface for emission of the solid laser medium 921 and the diameter of the beam enlarged by a beam expander 936, and is reflected from an optical member and led to a laser beam scanning system 930. The laser beam scanning system 930 reflects the laser beam and polarizes it in a desired direction, and the surface of the workpiece W is scanned with a laser beam LB outputted from a work region light condensing portion 940, and a process, such as printing, is carried out.
In terms of the configuration for exciting a solid laser medium, a one-directional pumping system where pumping light for exciting a solid laser medium enters through only one end surface for pumping and a laser beam is emitted through the other end surface, that is, so-called end pumping, is used, is known. In addition to this, a two-directional pumping system where the front and rear end surfaces of a solid laser medium are respectively irradiated with pumping light has also been proposed. In terms of two-directional pumping, a configuration where semiconductor lasers (Laser Diodes; LD), which are pumping light sources, are respectively placed against the end surfaces, as well as a configuration where pumping light from a single LD 928 is split by an optical fiber 932 so that a solid laser medium 921 is pumped from the two end surfaces, and the output comes from an output coupler 918, as disclosed in FIG. 34, is known (see for example Japanese Translation of Unexamined International Patent Publication H11 (1999)-505376).